Time-resolved absorption spectroscopy in shocked PETN single crystals

Extinction spectra of PETN and photodiode transmission records, with 50 and 0.5 ns resolution respectively, were obtained for shock compression along the [110] and [100] directions. Light extinction was found to be due to absorption; the contribution of scattering was measured to be below 0.001 %. Results for final stresses up to 10 GPa (stepwise loading) and initial stresses up to 5 GPa are presented. Broad band absorption in the visible appeared in PETN single crystals shocked to as low as 1 GPa. Absorption changes were measured as a function of time, stress, and crystal orientation. The process responsible for absorption occurred on a time scale faster than 0.5 ns. Work is in progress to identify the origin of the absorption.